Removal of model viruses, E. coli and Cryptosporidium oocysts from surface water by zirconium and chitosan coagulants

Christensen, Ekaterina; Nilsen, Vegard; Håkonsen, Tor; Heistad, Arve; Gantzer, Christophe; Robertson, Lucy J.; Myrmel, Mette

doi:10.2166/wh.2017.055

Cited by 10 publications

(3 citation statements)

References 25 publications

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“…In parallel, all the stock diluted samples (1:1 to 1:2 9 ) were also analysed for their ISAV Cq values using RT-qPCR. The absolute ISAV copy numbers (measured by RT-ddPCR) and Cq values (measured by RT-qPCR) from the undiluted stock sample were used to calculate the ISAV copy numbers in the stock dilutions (1:1 to 1:2 9 ) based on their Cq values, using the formula: N1 = N2 � (1+E) (CqN2-CqN1) [33], where N1 and N2 denote ISAV copy numbers in the diluted and undiluted stock samples, respectively, E is the amplification efficiency of the ISAV RT-qPCR (109% = 1.09), and Cq is the ISAV cycle quantification values.…”

Section: Quantification Of Isav Stockmentioning

confidence: 99%

Short communication: Evaluation of charged membrane filters and buffers for concentration and recovery of infectious salmon anaemia virus in seawater

et al. 2021

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Infectious salmon anaemia virus (ISAV) is the cause of an important waterborne disease of farmed Atlantic salmon. Detection of virus in water samples may constitute an alternative method to sacrificing fish for surveillance of fish populations for the presence of ISA-virus. We aimed to evaluate different membrane filters and buffers for concentration and recovery of ISAV in seawater, prior to molecular detection. One litre each of artificial and natural seawater was spiked with ISAV, followed by concentration with different filters and subsequent elution with different buffers. The negatively charged MF hydrophilic membrane filter, combined with NucliSENS® lysis buffer, presented the highest ISAV recovery percentages with 12.5 ± 1.3% by RT-qPCR and 31.7 ± 10.7% by RT-ddPCR. For the positively charged 1 MDS Zeta Plus® Virosorb® membrane filter, combined with NucliSENS® lysis buffer, the ISAV recovery percentages were 3.4 ± 0.1% by RT-qPCR and 10.8 ± 14.2% by RT-ddPCR. The limits of quantification (LOQ) were estimated to be 2.2 x 103 ISAV copies/L of natural seawater for both RT-qPCR and RT-ddPCR. The ISAV concentration method was more efficient in natural seawater.

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Section: Quantification Of Isav Stockmentioning

confidence: 99%

Short communication: Evaluation of charged membrane filters and buffers for concentration and recovery of infectious salmon anaemia virus in seawater

et al. 2021

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“…Quantification of SAV was done using the following formula: (Christensen et al 2017), where N 1 and N 2 are the SAV copy numbers in the sample and the IPC, respectively, E is the amplification efficiency, and Cq 1 and Cq 2 are the quantification cycle (Cq) values for the sample and IPC, respectively. The IPC was quantified using RT-ddPCR, performed as previously described (Weli et al 2021).…”

Section: Quantification Of Sav Copiesmentioning

confidence: 99%

Early detection of salmonid alphavirus in seawater from marine farm sites of Atlantic salmon Salmo salar

et al. 2021

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The traditional strategy for national surveillance of salmonid alphavirus (SAV) infection in Norwegian fish farms relies on a costly, time-consuming, and resource-demanding approach based on the monthly sampling of fish from all marine farms with salmonids. In order to develop an alternative surveillance method, a water filtration method was tested in parallel with the ongoing surveillance program at 7 Norwegian marine farm sites of Atlantic salmon Salmo salar L. with no current suspicion of SAV infection. During the period from May 2019 to January 2020, seawater samples were collected from the top layer water inside all net-pens at these 7 sites. The samples were concentrated for SAV by filtration through an MF-Millipore™ electronegative membrane filter, followed by rinsing with NucliSENS® Lysis Buffer, before RNA extraction and analysis by RT-qPCR. SAV was detected from seawater at an earlier stage compared to traditional sampling methods, at all sites where the fish tested positive for SAV. A significant negative relationship was observed at all sites between the SAV concentration found in seawater samples and the number of days until SAV was detected in the fish. This means that the fewer the SAV particles in the seawater, the more days it took until SAV was detected in the fish samples. Based on this, sampling of seawater every month for the surveillance of SAV has a great potential as an alternative method for early detection of SAV in Atlantic salmon farms.

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“…Quantification of SAV3 particles was performed based on the following formula: (Christensen et al 2017), where N 1 and N 2 represent the SAV3 copy number in the unknown sample and the calibrator, respectively and Cq 1 and Cq 2 represent the SAV3 detection in Cq values in the unknown sample and the calibrator, respectively. In order to estimate the number of viral particles in 1 l of tank water concentrated with the first CM (CM A ), copy numbers were multiplied with 25 × 2.4 × 1/R where R (re covery) is approximately 25%, as calculated according to Weli et al (2021).…”

Section: Quantification Of Sav3mentioning

confidence: 99%

Filtration, concentration and detection of salmonid alphavirus in seawater during a post-smolt salmon (Salmo salar) cohabitant challenge

et al. 2021

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Currently, the prevalence of salmonid alphavirus (SAV) in Norwegian Atlantic salmon farms is largely surveyed via sacrificing fish and sampling of organ tissue on a monthly basis. However, a more cost-efficient, straightforward, rapid, reliable, reproducible and animal welfare friendly method based on the detection of SAV in water could be considered as an alternative method. In the present study, such a method was developed and optimized through a 6 wk cohabitant challenge trial, using post-smolt Atlantic salmon Salmo salar L challenged with high or low doses of SAV subtype 3 (SAV3). Tank water and tissue samples from cohabitant fish were collected at 16 time points. SAV3 was concentrated from the water by filtration, using either electronegative or electropositive membrane filters, which were subsequently rinsed with one of 4 different buffer solutions. SAV3 was detected first in tank water (7 d post-challenge, DPC), and later in cohabitant fish organ tissue samples (12 DPC). The electronegative filter (MF-Millipore™) and rinsing with NucliSENS® easyMAG® Lysis Buffer presented the best SAV3 recovery. A significant positive correlation was found between SAV3 in the tank water concentrates and the mid-kidney samples. Based on these results, detection of SAV3 in filtrated seawater is believed to have the potential to serve as an alternative method for surveillance of SAV in Atlantic salmon farms.

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Removal of model viruses, E. coli and Cryptosporidium oocysts from surface water by zirconium and chitosan coagulants

Cited by 10 publications

References 25 publications

Short communication: Evaluation of charged membrane filters and buffers for concentration and recovery of infectious salmon anaemia virus in seawater

Short communication: Evaluation of charged membrane filters and buffers for concentration and recovery of infectious salmon anaemia virus in seawater

Early detection of salmonid alphavirus in seawater from marine farm sites of Atlantic salmon Salmo salar

Filtration, concentration and detection of salmonid alphavirus in seawater during a post-smolt salmon (Salmo salar) cohabitant challenge

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